xAI’s Colossus 2: Scaling Toward a Gigawatt AI Datacenter

Colossus 1 set the starting point

xAI’s first Colossus cluster in Memphis was built from scratch in 122 days. With approximately 200,000 H100 and H200 GPUs, along with about 30,000 GB200 NVL72 systems, it remains the largest fully operational, single-coherent AI cluster, excluding Google’s multi-datacenter training approach.

Colossus 1 uses roughly 300 MW of power. That figure is smaller than the gigawatt-scale facilities being developed by OpenAI, Meta, and Anthropic with support from hyperscaler partners.

The available estimates indicate that xAI’s expansion is not a one-time event. Its total datacenter capacity for a single training cluster was expected to exceed that of Meta Superintelligence and Anthropic by Q3 2025. Once GPUs are installed, the site could become the world’s largest single datacenter again. xAI still needs to raise the capital required for those GPUs, although Nvidia allocations were expected to support large-scale model training early in 2026.

Colossus 2: from zero to 200 MW in six months

The Colossus 2 project began on March 7, 2025, when xAI acquired a 1-million-square-foot warehouse in Memphis and two adjacent sites covering a combined 100 acres.

By August 22, 2025, 119 air-cooled chillers had been counted at the site, representing approximately 200 MW of cooling capacity. That capacity is sufficient for roughly 110,000 GB200 NVL72 systems. Images published in July also indicated that some racks had already been installed.

The construction timeline was approximately six months, compared with the 15 months required for the Oracle, Crusoe, and OpenAI project.

The site’s visible infrastructure raised a question: where would the power come from? The facility did not appear to include an onsite substation or turbines.

Power infrastructure across the Tennessee-Mississippi border

A May statement from the Greater Memphis Chamber said that turbines would not be located in Memphis. The explanation is that xAI developed a separate energy hub across the state border in Southaven, Mississippi.

In mid-2025, xAI acquired a former Duke Energy power plant in Southaven. Mississippi regulators subsequently granted temporary approval for gas turbines to operate there for up to 12 months without a permit.

To connect the power-generation site with Colossus 2, xAI began building supporting infrastructure near the datacenter. This included Tesla Megapacks and medium-voltage power lines between the two locations.

Scaling from 200 MW to 1.1 GW

The former Southaven power plant had seven 35 MW turbines in operation, providing a combined capacity of 245 MW. xAI’s broader power strategy relies on turbine-rental companies, including NYSE-listed Solaris Energy Infrastructure.

Solaris owns a 600 MW fleet of gas turbines, with approximately 400 MW serving xAI. xAI accounts for 67% of Solaris’s 1,700 MW orderbook, equivalent to roughly 1,140 MW. About 240 MW is associated with the Memphis Colossus 1 site. The remaining 900 MW is expected to be owned by a joint venture, with Solaris holding 50.1% and xAI holding 49.9%.

Approximately 460 MW was installed, operating, or under construction. The joint venture spent $112 million on capital expenditures during Q2 2025. Spending was expected to slow in Q3 before increasing again in Q4 2025 and Q1 2026.

Solaris expected to have more than 1.1 GW of fully operational turbine capacity serving xAI by Q2 2027. Approximately 425 MW remained available for contracting, creating a possible path to more than 1.5 GW of total gross power. Solaris also reported using selective, short-term sourcing of third-party power-generation capacity to respond more quickly to customer demand.

Possible datacenter layouts

From a power perspective, xAI had a path to more than 1 GW. The available land and building space presented several possible configurations:

• The 1-million-square-foot warehouse could be converted into a two-story datacenter. With a 40-foot building height and very high-density systems, 2 million square feet might support more than 1 GW.
• A second, smaller facility could be built on parcel 3.
• Additional land could be acquired, potentially in Mississippi near the Southaven power plant.
• A non-standard datacenter layout could allow the existing site to exceed 1 GW.

Funding requirements

Further expansion would require tens of billions of dollars in capital expenditures. At the time described, xAI had not yet generated substantial external revenue. A significant portion of its reported nine-digit annual recurring revenue was believed to consist of inter-company transfers from X.com to xAI.

A potential source of funding was the Middle East. Several investors in the region had existing relationships with Elon Musk and xAI:

• Saudi Arabia’s Kingdom Holding Company, 16.87% owned by the Public Investment Fund, retained a $1.9 billion stake in Twitter when Musk took the company private in 2022. It also held an $800 million stake in xAI before the merger with X.
• UAE-based Vy Capital provided $700 million in 2022 to support Musk’s acquisition of Twitter. It later invested in xAI’s Series C round alongside UAE state fund MGX.
• Qatar’s QIA retained a $375 million stake in Twitter and participated in xAI’s Series C round.

The Financial Times reported that xAI was preparing a new funding round worth tens of billions of dollars, potentially valuing the company at close to $200 billion. Saudi Arabia’s PIF was expected to play a significant role. Reports had also suggested a raise as large as $40 billion.

One possible structure would link the funding to construction of a large AI datacenter in Saudi Arabia. The region was already seeing rapid datacenter development, with available land and power for large AI campuses.

Internal sources of capital were also possible. After X.com and xAI were combined under X Holdings, some xAI revenue was believed to come from services provided to X.com, including Grok responses, search, advertising recommendation systems, and content creation. These transfers represent money moving between companies under the same ownership rather than entirely external demand.

Grok app revenue benefited substantially from Ani, although growth in that revenue stream had flattened in recent months. Additional features would be needed to support further growth.

Musk could also obtain funding through Tesla investments or loans secured against Tesla and SpaceX holdings. These options could provide tens of billions of dollars for Colossus 2, although the extent of Musk’s existing leverage was not publicly known.

Outlook

Colossus 2 represents a major expansion from the approximately 300 MW Colossus 1 site. By combining a rapidly converted datacenter facility in Memphis with gas-turbine capacity in Southaven, Mississippi, xAI developed a way to add power without placing turbines directly in Memphis.

The planned turbine capacity, additional land options, and potential funding sources could allow xAI to scale Colossus 2 beyond 1 GW. The remaining question is whether xAI can secure enough capital and GPUs to turn that infrastructure into a sustained frontier-model training operation.